Classifier



H. HARDlNGE Jan. 15, 1957 CLASSIFIER 4 Sh'eets -Sheet 1 Filed 001;. 13,1951 FIG. 4.

R m N D 1 R A H F- m R A H 1% ATTORNEYS H. HARDINGE Jan. 15, 1957CLASSIFIER 4 Sheets-Sheet 2 Filed Oct. 13, 1951 FIG. 6..

'IIII'IIIIAY'I'I'II'I /7 INVENTOR HARLOWE HARDINGE "II/MIA.

Jan. 15, 1957 H. HARDINGE CLASSIFIER 4 Sheet-Sheet 3 Filed 001.. l3,1951 INVENTOR" l-IAFILOWE moms:

- ATTORNEYS Jan. 15, 1957 HQHAR'DINGE 2,777,580

CLASSIFIER Filed Oct. 13, 1951 4 Sheets-Sheet 4 INVENTOR mamwe "moms:

FIG.

ATTORNEYfi CLASSIFIER- Harlowe Hardinge, York, Pa.

Application GctoberBl, 195 Serial No. 254,001-

13 Claims. (Cl. 209-444) This invention'relates generally-to classifyingapparatus and more particularly to apparatus for separating particleswhich settle at difierent rates in a liquid.

This application is a continuatiCn-ih-part of my copending applicationSerial No. 721,679, filed January 13, 1947, now Patent-No. 2,577,754,for a' Classifier containing claims to a method of classifying particlesby separation.

The-present apparatus isintended for the separation ofmaterials whichhave'diff'erent settling rates in liquid such as water; for instance,iron ore whichcontains materials ofvarying density such as silicaand-iron oxide. In free settling through Water, die particles whicharethe first-to settle to the bottom of any container may be the smallerrather than the larger particles, if the smaller particles are of theheavier material.- Where the material is composedof particlesalliofwhich are homogeneous, the size is ordinarily thedetermining-factorin the rate of settling. lt is to belmderstoodithatthis invention relates to the separation of particles of difierentratesof settling.

In general, the invention comprises apparatus including a surface orplatform moving-beneath a-liquid into which unsized pulp is dumpedorfed. Some of the fines in'the pulp remain in suspensionrinthe. liquidand the coarse particles settle upon the moving-platform carrying withthemthe remaining. fines. However, because the moving platform isinmotion through the. liquid,- for instance water, these fines tend. tobe dislodgedifrornthe coarse particles by reason of. the. washingaction-ofthe water on the coarse particles after. theyhavescomato reston the platform; Thus,.there is. a continualwashing action which tendsto maintainrthesfines tin-suspension, and the-eddy currents created bytheemotionof: thedeposited material on the moving platform underthe:liquid keeps the fines from settling, andevenzcausesthem to bebrought again into suspension after they have started to settle.

This type of classifier may 'bexusedwith grinding mills in accordancewith common practice.

The unsized pulp isfed tothe classifieratthe influent end a reasonabledistance away. from the; fines.:oyerfi'ow point. The coarseparticlesmayb'esent againto the mill to be reduced in size-and. may berededtottheclassifier. It is obvious that a-;change.in speed-of the moving platformwill also afiect thefines discharge. At very low speeds, themovingplatform will-cause-negli+ gible disturbance near thebottonrwithgthe resultthat fines, in addition to the coarse'particlesonce'deposited on the platform, will tend to remain there and becarriedxup to the. discharge with thepre-settled coarse particles. Thefaster the movement of. the platform, thezgreater; is

hired States Patent the agitationadjacent to it,'.and.-the greater thetendency to keep the finer particles in suspension.IfzthB;fiIl6l.P3lftieles of a. given size cannot remain'on the moving.surface without being washedofli, they willzstayinrsuspension and becomepart of the fluid medium, with the result that when a sufiicientnumberare present ,in the fluid '25- onto the disc.

Patented Jan.. 15, 1957 medium, they will flow as fines over theoverflow endof the classifier with the liquid.

The action and principles of this moving platform classifier. areradically difierent from other types that scrape the solids by rakes,drags, or screw flights over a stationary surface. In these types coarseparticles and fines are mixed together, or'fines are drained through thecoarse particles, thus holding them in the mass. The principle of thepresentinvention of depositingthe unsizedpulp on the moving submergedsurface permits the fines next settling on the moving surface tobewashed back into the liquid where they can be delivered to the finesdischarge point. The scraper which is employed" to remove the particlesdeposited on the movingplatform has in itself a squeezing action on thedeposited particles, and liquid andfines areforcedout; Thus, thematerial onthe-platform gets an additional desliming-as Well'as adewatering action.

In the drawings:

Figure-l is avertical sectional View, taken along the line 1 -1 ofFigure2, of one form of my apparatuswhich employs a horizontal rotating disc;

Figure 2' is a top plan view thereof;

Figure 3 is a vertical sectional view taken on the line 3--3-of' Figure4 of'another form ofthe invention;

Figure 4 is a top plan view thereof;

Figure 5 is a: vertical sectional view of a further form of theinvention; taken on the line 5-5 of Figure 6;

' Figure 6 is a top plan view thereof;

Figure 7 is averticalsectional view of a still further format theinvention, taken on the line '77 of Figure 8;

Figure -8 is a top :plan view thereof;

Figure 9"is a detail-view showing one form of'bafile with the waterdischarge therethrough;and

Figure. 10 is a detail view showing another form of baffie with thewater. dischargev therethrough.

Referring to the drawings, numeral 12 designates a tank which iscircular in-configuration and provided'with a'. fines overflowdischargechute 15.. Adapted to rotate near; thebottonr i :the tank 12 isadisc 17 suspended on a shaft. 13 which is driven by suitable gearing 19connected to a sourcezof, power, not shown. The shaft 18 is restrictedin diameter as illustrated. at 24} where it passes through the disc17and a holding nut 21, or other similar. holding member, holds the discv17 on the shaft 18 so that it is rotated'with the shaft 18.

Unsized pulp is-fed through a duct 22 onto thesurface of water 25intl'l8't2ll1k.12;. The tank is. provided with acollecting trough 26 atoneend, in which is mounted a conveyor screw 27- drivenbya source of power;not shown, which isadapted-to deliver the. coarse washed sands to acoarsesandsdischarge outlet 28.

Adaptedto scrape. the :coarse particles 29 from the disc 17 is ascraper. member. 3! It-has-been. found that the scraper. 30 shouldbeset'at enough-of an angle toithedirection of motion-of the coarseparticles 29 to scrape them ofi without permitting them-to be piled uptotoo great an extent adjacent the scraper. In other words, the'angle ofthe. scraper, ithas been found, should'be setso as tofeed the. coarseparticles-with comparative ease into the discharge chute 26.

ReferringtoFigures l.and 2 of the drawings,.it will beseen that the.unsized pulp is fed through the feed pipe 22 onto. the rotating disc 17,and fallsthrough-the water While. falling through the water, thefinesbecome suspended in thewater. The coarse par.- ticles, after theynear the upper surface of the rotating disc 1.7. and when they touch therotating disc,.are .subjected to eddycurrents which wash out'more of the:fines. These fines in suspension pass over the fines overflow 15'. The.coarse particles. on they disc 17'are subjectedto.-a; washingaction by,the. water during therotation of the.

disc until they reach a point adjacent the scraper 30, at which pointthey are scraped off into the discharge chute 26. The material scrapedofi the disc 17 falls into the bottom of the chute, and is fed by theconveyor screw 27 to the coarse sands discharge point 23. Here thecoarse particles can be sent again to the mill and re-fed through theunsized pulp feed pipe 22 for re-processing. The bottom surface of thedisc 17 is provided with one or more narrow radial scraper vanes 23, tokeep materials from building up underneath the disc 17 as it rotates inThe great efficiency of'the present invention is in part due to the eddycurrents adjacent the surface of the disc. The coarse particles as theyapproach the disc 17 are subjected to a washing because of these eddycurrents which loosen the fines and tend to keep them in suspension.Moreover, the particles, after they rest on the upper surface of thedisc 17, are subjected to eddy currents and washing as the depositedparticles move along with the rotating disc. This tends to remove thefines from the coarse particles and causes a very eflicient operation ofthe classifier.

The coarse particles and the fines are not mixed together and the finesare not drained through the coarse as has been the case with otherclassifier systems. It is to be emphasized that the movement of therotating platform or disc 17 causes the fines to be washed back into theliquid zone. Moreover, the action of the scraper 30 and the conveyorscrew 27 is to squeeze the fines and the water out of the coarseparticles just at the point that the coarse particles are dischargedfrom the classifier.

The greater the speed of rotation of the disc 17, the greater is thewashing action of the water. It is to be noted that there is greaterwashing action near the periphery of the disc 17 than near the centerbecause of the greater speed of travel of points near the periphery thanof points near the center.

The same principles of operation are true of the em: bodiment disclosedin Figures 3 and 4. In this case, the tank 12 is provided with anupwardly sloping bottom 31 and the disc 17 is arranged to rotateparallel to the bottom 31. The scraper 3G is set so as to scrape thehigher side of the disc 17. The disc is arranged so that its higher sideduring its rotation continually emerges above the surface of the water25 and there is a high portion of the disc 17 which lies above the waterand is indicated by the numeral 32. It is preferable to scrape thecoarse sands into a coarse sands discharge chute 35 by means of thescraper 36 positioned at the high point 32. Although the dischargeposition of the settled solids is shown as being above the surface or"the liquid, they could be under the liquid but at a higher point thanthe lower point of the disc. The liquid adjacent the disc 17, in eithercase, tends to rotate with the disc and the solids on the disc but eddycurrents are produced in the liquid.

Whenthe discharge is above the surface of the water, some water iscarried above the surface of the liquid and washes back, carryingwith-it those fines which are lightly resting on the disc or on thecoarse particles on the disc. The liquid velocity at this point willcarry them back and not permit them to be discharged with the moretenacious portion of the load which are the heavier, coarser sizes. Theresult of this action, particularly where the discharge is above thesurface of the liquid, is that the fines will remain in suspension inthe tank and they will be built up to a degree where they tend to remainin suspension, and eventually will go over as fines at the overflow 15.

Another form of the invention employing the principlesset forth is shownin Figures and 6. In this form'of the invention, the suitably supportedtank 12 is elongated as is the sloping bottom 31 to receive twoadditional rotatable discs 36 and 37, each provided with scrapers 30.The disc 17 is spaced from the bottom of the tank and its'higherperipheral edge overlaps the lower edge of the disc 36 for a reasonwhich will become apparent. Simi- 4 larly, the higher edge of the disc36 overlaps the lowe edge of the disc 37 and the high point 32, as inthe previous form of the invention, is adjacent the coarse sandsdischarge chute 35.

As shown in Figure 6, the discs 17 and 37 rotate clockparticles are thusfurther agitated with additional fines being separated from the coarseparticles which are transferred to the oppositely rotating disc 37 bythe scraper it) when the operation is repeated. As the high point 32 ofthe disc 37 is out of the water 25, the scraper will squeeze the coarseparticles at this point and discharge them into the chute 35. It will bereadily apparent that the more thorough classifier action is provided bythis form of the invention.

A further form of the'invention also employing the classifier principlesset forth herein is shown in Figures 7 and 8. This form of the inventionis similar to the form shown in Figures'S and 6 except that anadditional rotat ing disc 38 is employed and positioned out of line withrespect to the discs 17, 36 and 37. Thus, the fines overflow dischargechute 15 is out of line with the coarsesands discharge chute 35 which isshown as discharging into a ball mill M. The reground unsized pulpisthen discharged into the tank 12 directly over the disc 17 by the chute40 where it is again classified in the manner described. It will benoted that in this form of the invention only the discs Hand 36 aresubmerged in the water 25.

Under certain circumstances it is desirable that additional liquid beadded in the scraper zone. While the scraper could be hollow and beprovided with parts and a source of fluid, I have shown in Figures 9 and10 two alternate methods of supplying water to the scraper zone. InFigure 9, a pipe 40 having a nozzle 41 is fixed to the scraper 30adjacent its lower edge and connected to a source of fluid which isdischarged through the solids. In Figure 10, I have shown a pipe 42having a nozzle 43 which discharges fluid over the solids.

The addition of relatively clean liquid in the scraper zone'enables afurther desliming action to be obtained. This added fluid tends to carryaway with it more of the slimes and fines of a size smaller than thatforming the major portion of the mass, thus creating an additionalsizing action by returning these fines and slimes back into the poolwith the liquid and permitting the scraped sands to be discharged withless unwanted fines or slimes there- 1n.

The scrapers 30 acting with the various discs effect a very thoroughwashing and desliming of the oversize or coarser particles which arealso thoroughly squeezed thereby and rendered suitable for feeding tothe ball mill. The pulp is thus submitted and resubmitted to the ballmill and classifier until it passes over-the discharge chute 15 asfines. It will thus be readily. apparent that the apparatus comprisingthe present invention does not wash the fines through the coarseparticles but prevents the mixing of the fines and coarse particles to agreater extent than is possible by the usual scraping with rakes, or byemploying drags or screw flights overa stationary surface.

It is to be understood that the forms of the invention herewith shownand described are to be taken as preferred examples of the same and thatvarious changes in the shape, size and arrangement of parts mayberesorted to without departing from the spirit of the invention or thescope of the subjoined claims.

I claim:

1. An apparatus for classifying particles which settle at differentratesin a liquid comprisinga containerhaving:a'liquid'therein, means fordischarging particlesto be classified into the container, a; disc: inthe container upon which the settled particles. are adapted to collectlying underneath the surface of the liquid, means; to rotate the discwhereby eddy currents are' generated in the liquid, and stationaryscraper means angularly. disposed across a portion of said disc surfaceto remove continuously the settled particles from saidzdisc.

2. A classifier comprising a tank for liquid, a rotating disc at leastpartially submerged'nnder the surface of the liquid and. having itssurface; atan angle to thehorizontal surface. of. the .liquid,,means wfordischarging liquid and, solids'into thetankonto. therotating disc,means for discharging liquid with suspended solids therein from thetank, and a scraper for removing continuously the solids that havesettled on the rotating disc said scraper being positioned at a pointnear the high point of the disc.

3. An apparatus for classifying particles which settle at differentrates in a liquid comprising a container having a liquid therein, meansfor discharging particles to be classified into the container, a discupon which the settled particles are adapted to collect lying underneaththe surface of the liquid and having its surface inclined at an angle tothe horizontal, means to rotate the disc Whereby eddy currents aregenerated in the liquid, and a scraper to remove continuously thesettled particles from said disc at a high point thereof.

4. A classifier comprising a tank for liquid, a rotating disc at leastpartially submerged under the surface of the liquid and having its uppersurface at an angle to the horizontal surface of the liquid, means fordischarging liquid and solids into the tank onto the rotating disc,means for discharging liquid with suspended solids therein from thetank, and means for removing continuously the solids that have settledon the rotating disc at a point near the high point of the disc, saidliquid and suspended solids discharge being in actual alignment withsaid settled solids removing means.

5. A classifier comprising a tank for liquid, a plurality of rotatingdiscs mounted in said tank and having their upper surfaces at an angleto the horizontal surface of the liquid, the major portion of thesurface area of said discs being submerged beneath said liquid, meansfor discharging liquid and solids into the tank onto the rotating discs,means for discharging liquid with suspended solids therein from thetank, means for transferring settled solids upwardly from disc to discto a high point of the discs and means for removing the solids from thetank.

6. A classifier comprising a tank for liquid, a plurality of rotatingdiscs mounted in said tank and having their upper surfaces at an angleto the horizontal surface of the liquid, the major portion of thesurface area of said discs being submerged beneath said liquid, meansfor discharging liquid and solids into the tank onto the rotating discs,means for discharging liquid with suspended solids therein from thetank, means for transferring settled solids upwardly from disc to discto a high point of the discs and means for removing the solids from thetank, said last mentioned means comprising a discharge chute and ascraper blade positioned in said tank closely adjacent the upper surfaceof said point to divert the solids into the chute.

7. A classifier comprising a tank for liquid, a plurality of rotatingdiscs mounted in said tankand having their upper surfaces at an angle tothe horizontal surface of the liquid, the major portion of the surfacearea of said discs being submerged beneath said liquid, means fordischarging liquid and solids into the tank onto the rotating discs,means for discharging liquid with suspended solids therein from thetank, means for transferring settled solids upwardly from disc to discto a high point of the discs and means for removing the solids from thetank, said transferral means comprising a plurality of scraper. bladesmounted inthetank.v closely; adj'acenttthe upper surface .of eachrdiscatitshigh point and, actingto divert settled solids from a disc to thenext higher disc.

8. A classifier comprising a tank forliquid, a; plurality of rotatingdiscsmounted in the tankand, having their upper surfaces at an angle tothe horizontal surface of the liquid,- a plurality of the-discsbeingpositioned above the surface of the liquid,- meansfor dischargingliquid and solids into the-tank ontothe submerged rotating discs, meansfor discharging-liquid with suspended solids therein from the tank, andmeans for transferring the solids that have scttledon thesubmergedrotating discs'upwardly fromdisc to disc to the highpoint ofthe disc, and scraper means for removing the collected solidsfronrthefinal disc, said scraper means acting to squeeze the moisture from thesettled solids after their movement above the liquid level.

9. A classifier comprising a tank for liquid, a plurality of rotatingdiscs mounted in the tank and having their upper surfaces at an angle tothe horizontal surface of the liquid, a plurality of the discs beingpositioned above the surface of the liquid, means for discharging liquidand solids into the tank onto the submerged rotating discs, means fordischarging liquid with suspended solids therein from the tank, andmeans for transferring the solids that have settled on the submergedrotating discs upwardly from disc to disc to a point near the high pointof the discs, and scraper means for removing the collected solids fromthe final disc, said scraper acting to squeeze the moisture from thesettled solids after their movement above the liquid level, said meansfor discharging liquid with suspended solids and said solids removingmeans being out of axial alignment.

10. A classifier comprising a tank for liquid, a rotating disc at leastpartially submerged under the surface of the liquid and having itssurface at an angle to the horizontal surface of the liquid, means fordischarging liquid and solids into the tank onto the rotating disc,means for discharging liquid with suspended solids therein from thetank, means for removing the solids that have settled on the rotatingdisc at a point near the high point of the disc, and means fixed to thebottom of said disc and effective to prevent the accumulation of solidsthereunder.

11. A classifier comprising a tank for liquid, a rotating disc at leastpartially submerged under the surface of the liquid and having itssurface at an angle to the horizontal surface of the liquid, means fordischarging liquid and solids into the tank onto the rotating disc,means for discharging'liquid with suspended solids therein from thetank, means for removing the solids that have settled on the rotatingdisc at a point near the high point of the disc, and means fixed to thebottom of said disc and efiective to prevent the accumulation of solidsthereunder, said last mentioned means comprising a substantiallyradially positioned scraper vane.

12. A classifier comprising a tank for liquid, a rotating disc at leastpartially submerged under the surface of the liquid and having itssurface at an angle to the horizontal surface of the liquid, means fordischarging liquid and solids into the tank onto the rotating disc,means for discharging liquid With suspended solids therein from thetank, and means for removing the solids that have settled on therotating disc at a point near the high point of the disc, said lastmentioned means including additional means for introducing fluid intothe solids adjacent the scraper.

13. A classifier comprising a tank for liquid, a rotating disc at leastpartially submerged under the surface of the liquid and having itssurface at an angle to the horizontal surface of the liquid, means fordischarging liquid and solids into the tank onto the rotating disc,means for discharging liquid with suspended solids therein from thetank, and means for removing the solids that have settled on therotating disc at a point near the high point of the disc, said lastmentioned means includingadditional means for introducing fluid over thesolids adjacent the scraper.

References Cited in the file of this patent UNITED STATES PATENTSKligour Oct. 22, 1889 Garrison May 27, 1890 Besly -May 1, 1894 PardeeApr. 30, 1895 Bouk Aug. 20, 1895 Don Apr. 9, 1907 Guest Apr. 11, 1916Jackson Sept. 16, 1919 8 Nesbitt Jan. 6, 1925 Peale June 30, 1931Hinkley Jan. 1, 1935 Falkiner Mar. 24, 1936 Haultain Jan. 11, 1938 DullJan. 27, 1942 Weber Nov. 17, 1942 Finney Mar. 18, 1947 Hardinge Dec. 11,1951 FOREIGN PATENTS Great Britain Aug. 29, 1944 France Mar. 20, 1926France May 11, 1933

